BOSTON (UPI) -- Animal rescuers in Boston said a couple taking a taxicab in the city discovered a large American bullfrog under the vehicle's back seat.

Brian O'Connor, the Animal Rescue League's manager of rescue services, said the couple found the 6-inch frog at about 3 p.m. Saturday and had the driver make a detour to the league's headquarters, the Boston Herald reported Monday.

"They were taking a cab somewhere in Boston when all of a sudden they found a huge American bullfrog under the back seat," O'Connor said. The cab driver had no idea.